Reanalyzed Fossils Could Be Last Known Homo erectus Specimens

A mass death event claimed the hominins’ lives and likely resulted from changing environmental conditions.

Emily Makowski

Dec 18, 2019

ABOVE: A Homo erectus skull found in Kenya that was not analyzed in the new study.FLICKR, HJ_WEST

Homo erectus fossil remains discovered decades ago in Central Java, Indonesia, represent the last known individuals of the ancient hominin species, according to a press release. The new findings help to clarify how long H. erectus existed. The species, which evolved 2 million years ago, was the first to walk upright and to migrate from Africa.

Paleontologist Yan Rizal at Bandung Institute of Technology in Indonesia and colleagues used radioactive dating to analyze 12 skulls and two lower leg bones discovered between 1931 and 1933. Over the years, the age of these fossils has been difficult to determine due to the geological complexity of the excavation site, an area near the Solo River at Ngandong that was experiencing changes in environmental conditions when the hominins died during a mass death event. Previous estimates of the fossils’ age ranged widely, from 550,000 to 27,000 years old, but the analysis from Rizal and colleagues suggests the fossils are between 117,000 and 108,000 years old, representing the last known occurrence of H. erectus.

These specimens confirm that the species likely went extinct due to climate change, study coauthor Russell Ciochon, a biological anthropologist at the University of Iowa, tells CNN. “The open woodland was replaced by a rainforest. No Homo erectus fossils are found after the environment changed, so Homo erectus likely was unable to adapt to this new rainforest environment,” he says.